1. Technical Field
The disclosure relates to a calibration device, and in particular, to an impedance calibration device and method.
2. Related Art
When a process variation happens during a semiconductor manufacturing process, the characteristic of a component in an integrated circuit (IC) changes accompany with the process variation, for example, a resistance value of impedance varies. The variation of a resistor may have different influences on different electronic components. For example, a change of a resistor causes a bandwidth variation in a filter. For another example, the variation of the resistor causes a frequency variation in an oscillator. For another example, in a communication system, impedance matching between a transmitting end and a receiving end is strictly regulated. Impedance mismatching causes risks of signal distortion and even signal interruption, and a change of a resistor may cause the problem of impedance mismatching. Therefore, how to overcome a variation of the resistance value caused by the process variation is always a challenge to the design of an IC.
Traditionally, a trimming manner is adopted to calibrate the resistance value, or the process control is used to reduce a variation amount of the process. However, the former increases the testing time and cost, while the latter increases the manufacturing cost of an IC, both of which are uneconomical.
In view of this, a new architecture is put forward to accurately calibrate an internal impedance of an IC and to further reduce the cost.